Multiphase Analysis of a Solder Joint Using EBSD Alone

The increasing compliance to RoHS regulations (Reduction of Hazardous Substances) in electronics has promoted the development of lead-free solder. Depending on their composition solder alloys produce different multiphase mixtures. Analyzing such samples with EBSD is a big challenge, because phases vary in hardness, which makes sample preparation very difficult.

In this example six different phases could be determined:

Tin (Sn): tetragonal

Copper, nickel (Cu, Ni): cubic

Cu6Sn5: hexagonal

Ni3Sn4: monoclinic

AuSn4: orthorhombic

Ag3Sn: orthorhombic (hex)

The hit rate for each phase depends strongly on preparation success, meaning how well an even sample surface could be attained and local topography suppressed.